Wednesday, March 19, 2008

Revised Bracketology

If you read my post yesterday, forget it. I slept on it and decided there was a less arbitrary, simpler, and more statistically reliable way to predict the probable outcomes of NCAA tournament games. I call it "Neutral Site Point Value over Average".

Method

I went way back in NBA history to the days when they played true "neutral site" games (for example, the Lakers would play the Celtics in Michigan. I guess it was the days before TV contracts) and discovered that team's average neutral site performances usually ended up splitting the difference between their overall performance and their road performance. Relying on that, here is my method for predicting neutral site outcomes:

1. Average each team's Overall and Road offensive and defensive efficiencies. The product is the team's likely "Neutral Site" Offensive and Defensive efficiencies.

2. Get each team's "Opponent" Offensive and Defensive efficiencies. This is your schedule neutralizer.

3. Determine each team's "Point Value over Average" by subtracting the team's neutral site efficiencies from their opponent's opposite efficiency. (For instance, Wisconsin's neutral site offensive efficiency is 105.8. Their Opponent's defensive efficiency for the season is 95.4. Therefore, Bucky's offensive "Point Value over Average" for neutral site games is +10.4.)

3. Add both teams average number of possessions per game and divide by 2. The outcome is the likely number of possessions when the teams play.

4. Now use that possession number to play out each team's "average game". In other words, multiply each team's neutral site efficiency by the possession number Now you have an average "score" each team would expect on a neutral site given the number of possessions.

5. Take each team's "Point Value over Average" and apply it to the other team's "average game". (For instance, comparing Wisconsin to Georgetown. Wisconsin's neutral site PVOAs are +10.4 on offense and -19.3 on defense. Georgetown's are +12.2 and -14.1. Georgetown's average neutral site game score is projected to be Gtown 67.3, Opponent 58.4, and Wisconsin's is Wisco 65.8, Opponent 54.6. Therefore, if the two teams met, from Gtown's perspective the score would be Gtown 66.8, Wisco 51.7, and from Wisco's perspective the score would be Wisco 68.8, Gtown 48.)

6. Take each team's PVOA game score and average the results. That is your projected outcome. In the above example, the predicted outcome would be Wisconsin 60, Georgetown 57.

What it tells us

All this is telling us is the likely result of the game if each team plays their average game. And, isn't that about the best you can hope for? If you use this method, you are playing the probabilites.

I tested the method on tonight's meaningless "play-in" game between Coppin State and Mount Saint Mary's. The predicted score was Mount Saint Mary's 65, Coppin State 58. The actual score was MSM 69, C State 60, so it was close and it got the victor right.

New Tournament Picks

First Round (Picks in Bold; notes where appropriate)

1. North Carolina-MSM

2. Indiana 72 Arkansas 67

3. Notre Dame-George Mason

4. Washington State - Winthrop

4. St. Joes 70 Oklahoma 65

6. Louisville-Boise St

7. Butler-South Alabama

8. Tennessee

9. Kansas

10. Kent St-UNLV

11. Clemson

12. Vanderbilt

13. Kansas St. 64 USC 63

14. Wisconsin

15. Davidson

16. Georgetown

17. UCLA

18. Texas AM

19. Drake

20. UConn

21. Purdue (barely)

22. Xavier

23. Arizona

24. Duke

25. Memphis

26. Miss St

27. MSU

28. Pitt

29 Marquette

30 Stanford

31 St Mary's (just barely)

32 Texas

Second Round

Its getting late, so I'm just going to list the teams and explain them later. Some are very close calls.

Same here. Have you looked at how accurately this formula would have predicted the outcome of last year's tournament? That would be very interesting to see and add a lot more validity to your process. I know that's probably a lot of work you may not feel like doing at this point though

Ron, Frank, thank you... but, ah, did I mention I came in last last year? That said, if this doesnt work I will conclude the tournament is so arbitrary that its unpickable (and winnable only by those chicks who choose teams based on prettiest uniform colors or where she wants to live... they always seem to win!).

Wils, you are absolutely right, 100% correct, but if I have to punch one more number or look at one more stat sheet I will suffer a nervous breakdown, so I'm just going to let it ride.

In other words, this year will be the test year.

For what its worth, my picks seem to mirror the Sagarin picks, and that method is proven, so you never know.

I'm pretty satisfied with the formula's logic, though. Basically, unless I took a wrong turn that I don't see, what the formula tells you is what ought to happen, based on a season's worth of evidence, if each team plays its average game... in other words its more or less based solidly on the most probable (but still nowhere near guaranteed) outcome. And that's probably the best method you can use to pick one of these "one-off" "anything can happen" tournaments.

At any rate, I'd rather go down in flames with some sort of logical methodology than spend another year kicking myself for picking this team or that team based on this "gut feeling" of mine or that one.

Let me phrase it another way... I have no confidence that the picks are right, but I have a lot of confidence that they are the "best guess" I could make given the information, if you know what I mean.

For instance, I just went back and calculated last year's championship game. My method predicted Florida wins, 77-69. They actually won 84-75, but that's because Florida played so well offensively (or, OSU stunk so bad on defense) that Florida outperformed its own home offensive efficiency average in the game.

Now, there's no way you could confidently forecast that would happen in the championship game against a decent defensive team. The best you can do is forecast what most likely will happen, and let the chips fall where they may.